1. Field of the Invention
The present invention relates to the regeneration of a methanol-reforming catalyst. More specifically, this invention is concerned with a method for the simple and easy regeneration of a catalyst which has been used in the production of a hydrogen-containing gas by reforming of methanol, if necessary, in the presence of water.
2. Description of the Prior Art
In the presence of a catalyst, methanol can be rather easily reformed into a gas composed principally of hydrogen or, in the presence of water, into a gas having a still higher hydrogen content. (The latter reforming may be specifically called "steam reforming". The term "reforming" as used herein should however be interpreted as embracing not only reforming in the absence of water but also reforming in the presence of water except for cases where specific reference to steam reforming is needed.)
Numerous catalysts have heretofore been proposed for the reforming of methanol, including catalysts with a platinum-group metal such as platinum or vanadium supported on a carrier such as alumina, catalysts with one or more of the base metals of groups IB, IIB, IVA and VIII of the periodic table--such as copper, nickel, chromium and zinc--supported on such a carrier, and catalysts composed of one or more of the oxides of such base metals.
Among these, catalysts containing copper as a principal component include the following proposals:
(1) Catalysts containing copper oxide and chromium oxide as principal ingredients and also the oxides of manganese, barium and the like (see Japanese Patent Publication No. 11274/1979). PA1 (2) Catalysts containing copper oxide and zinc oxide as principal components and also chromium oxide (see Japanese Patent Laid-Open No. 174138/1982) or also aluminum oxide, manganese oxide, boron oxide and the like (see Japanese Patent Laid-Open No. 131501/1984). PA1 (3) Catalysts containing copper oxide, nickel oxide and aluminum oxide as principal components and also lithium, sodium, potassium and the like (see Japanese Patent Laid-Open No. 224046/1989). PA1 (4) Coprecipitated, copper-containing, two-component catalysts such as copper/aluminum oxide [see H. Kobayashi, N. Takezawa and C. Minochi, Chem. Lett., 1347 (1976)].
To the best knowledge of the present inventors, these copper-containing catalysts are however accompanied by the problem that their activity and selectivity are progressively reduced when a long-term, continuous operation is practiced.